Vlag Capacities; Vlags Versus Port Lags - Lenovo RackSwitch G8264 Application Manual

VLAG Capacities

VLAGs versus Port LAGs

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G8264 Application Guide for ENOS 8.4
Servers or switches that connect to the VLAG peers using a multi‐port VLAG are
considered VLAG clients. VLAG clients are not required to be VLAG‐capable. The
ports participating in the VLAG are configured as regular port LAGs on the VLAG
client end.
On the VLAG peers, the VLAGs are configured similarly to regular port LAGs,
using many of the same features and rules. See Chapter 10, "Ports and Link
Aggregation" for general information concerning all port LAGs.
Each VLAG begins as a regular port LAG on each VLAG‐peer switch. The VLAG
may be either a static LAG (portchannel) or dynamic LACP LAG, and consumes
one slot from the overall port LAG capacity pool. The LAG type must match that
used on VLAG client devices. Additional configuration is then required to
implement the VLAG on both VLAG peer switches.
You may configure up to 64 LAGs on the switch, with all types (regular or VLAG,
static or LACP) sharing the same pool.
The maximum number of supported VLAG instances is as follows:
With STP off: Maximum of 52 VLAG instances

 With STP on:
PVRST/MSTP with one VLAG instance per VLAN/STG: Maximum of 52

VLAG instances
PVRST/MSTP with one VLAG instance belonging to multiple

VLANs/STGs: Maximum of 20 VLAG instances
Each LAG type can contain up to 32 member ports, depending on the port type and
availability.
Though similar to regular port LAGs in many regards, VLAGs differ from regular
port LAGs in a number of important ways:
A VLAG can consist of multiple ports on two VLAG peers, which are connected

to one logical client device such as a server, switch, or another VLAG device.
 The participating ports on the client device are configured as a regular port
LAG.
 The VLAG peers must be the same model, and run the same software version.
 VLAG peers require a dedicated inter‐switch link (ISL) for synchronization. The
ports used to create the ISL must have the following properties:
ISL ports must have VLAN tagging turned on.

ISL ports must be configured for all VLAG VLANs.

ISL ports must be placed into a regular port LAG (dynamic or static).

A minimum of two ports on each switch are recommended for ISL use.

 Dynamic routing protocols, such as OSPF, cannot terminate on VLAGs.